On Thu, Jul 29, 2010 at 2:25 AM, Ben Dooks <ben@xxxxxxxxxxxx> wrote: > On 28/07/10 04:17, MyungJoo Ham wrote: >> Many MUX and clock dividers have a status bit so that users can wait >> until the status is stable. When corresponding registers are accessed >> while a clock is not stable, we may suffer from unexpected errors. >> >> Therefore, we introduce a mechanism to let the operations related with >> updating SRC/DIV registers of clksrc-clk wait for the stabilization: >> clk_set_parent, clk_set_rate. >> >> In order to use this feature, the definition of clksrc_clk should >> include reg_src_stable or reg_div_stable. With effective rec_src_stable >> values, clk_set_parent returns with a stabilized SRC register and >> with effective rec_div_stable values, clk_set_rate returns with a >> stabilized DIV register. If .reg field is null, its (either SRC or DIV) >> register's status is not checked and returned without waiting; i.e., >> some MUX/DIV may not need this feature. >> >> When setting reg_*_stable, .size is used to tell the value of "stable". >> If .size = 0, the stable status is 0 and if .size = 1, the stable status >> is 1. >> >> Signed-off-by: MyungJoo Ham <myungjoo.ham@xxxxxxxxxxx> >> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx> >> --- >> arch/arm/plat-samsung/clock-clksrc.c | 13 +++++++++++++ >> arch/arm/plat-samsung/include/plat/clock-clksrc.h | 10 ++++++++++ >> 2 files changed, 23 insertions(+), 0 deletions(-) >> >> diff --git a/arch/arm/plat-samsung/clock-clksrc.c b/arch/arm/plat-samsung/clock-clksrc.c >> index 46d204a..5ff17ad 100644 >> --- a/arch/arm/plat-samsung/clock-clksrc.c >> +++ b/arch/arm/plat-samsung/clock-clksrc.c >> @@ -68,6 +68,12 @@ static int s3c_setrate_clksrc(struct clk *clk, unsigned long rate) >> val |= (div - 1) << sclk->reg_div.shift; >> __raw_writel(val, reg); >> >> + if (sclk->reg_div_stable.reg) { >> + do { } while (((__raw_readl(sclk->reg_div_stable.reg) >> >> + sclk->reg_div_stable.shift) & 1) >> + != sclk->reg_div_stable.size); >> + } >> + >> return 0; >> } > > you could move the code for this out to a separate inlined function to > avoid it being here twice, and possibly make it flow better. > Ok. Inlining those is done with the v2 patch. Thanks. >> @@ -93,6 +99,13 @@ static int s3c_setparent_clksrc(struct clk *clk, struct clk *parent) >> clksrc |= src_nr << sclk->reg_src.shift; >> >> __raw_writel(clksrc, sclk->reg_src.reg); >> + >> + if (sclk->reg_src_stable.reg) { >> + do { } while (((__raw_readl(sclk->reg_src_stable.reg) >> >> + sclk->reg_src_stable.shift) & 1) >> + != sclk->reg_src_stable.size); >> + } >> + >> return 0; >> } >> >> diff --git a/arch/arm/plat-samsung/include/plat/clock-clksrc.h b/arch/arm/plat-samsung/include/plat/clock-clksrc.h >> index 50a8ca7..282821d 100644 >> --- a/arch/arm/plat-samsung/include/plat/clock-clksrc.h >> +++ b/arch/arm/plat-samsung/include/plat/clock-clksrc.h >> @@ -45,6 +45,13 @@ struct clksrc_reg { >> * @sources: the sources for this clock >> * @reg_src: the register definition for selecting the clock's source >> * @reg_div: the register definition for the clock's output divisor >> + * @reg_src_stable: the register definition to probe if reg_src is >> + * stabilized after the update of reg_src. It is "stabilized" if >> + * reg[shift] == size. If reg == NULL, this stable reg is not looked >> + * up. Thus, in S5PV210, size is usually 0. >> + * @reg_div_stable: the register definition to probe if reg_div is >> + * stabilized after the update of reg_div. Same mechanism with >> + * reg_src_stable. >> * >> * This clock implements the features required by the newer SoCs where >> * the standard clock block provides an input mux and a post-mux divisor >> @@ -61,6 +68,9 @@ struct clksrc_clk { >> >> struct clksrc_reg reg_src; >> struct clksrc_reg reg_div; >> + >> + struct clksrc_reg reg_src_stable; >> + struct clksrc_reg reg_div_stable; >> }; >> >> /** > > -- MyungJoo Ham (함명주), Ph.D. Mobile Software Platform Lab, Digital Media and Communications (DMC) Business Samsung Electronics cell: 82-10-6714-2858 -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html